Resizing die for spent straight wall cartridges

ABSTRACT

A die for resizing spent straight wall cartridges that is suitable for use in a reloading press. The die contains a pair of spaced apart resizing rings that are arranged to size the bullet chamber of the cartridge casing to a smaller diameter than the charge chamber of the casing to improve the firing performance of the reloaded cartridge.

FIELD OF THE INVENTION BACKGROUND OF THE INVENTION

This invention relates to a die for resizing a straight wall cartridgeafter the cartridge has been fired.

BACKGROUND OF THE INVENTION

Many gun owners elect to reload their spent cartridges for reuse ratherthan purchase new cartridges. When fired by a rifle or pistol, thefiring pin of the weapon initially strikes the cartridge primer which,in turn, ignites the powder charge that is stored in the rear section ofthe shell casing adjacent to the primer. The ignited charge generates ahigh internal pressure within the casing that causes the casing toexpand against the firing chamber wall of the weapon while at the sametime propelling the bullet contained in the front section of the casingthrough the barrel of the weapon toward an intended target. After thecartridge has fired and the bullet is expelled, the casing contractsback toward its original size and shape. However, the casing generallycannot completely attain its original configuration. Accordingly, theshell casing must be resized to its original shape prior to reuse andany remaining primer material removed from its primer pocket located atthe proximal end of the casing.

Typically, resizing of a shell casing is accomplished by the gun ownerusing a resizing die that is generally mountable in a hand operatedpress. The die is typically secured in the stationary head of the pressand is axially aligned with a cartridge which is secured in the movableram of the press with the open end of the casing facing the die. Thecartridge is passed into the die wherein the casing surface is reworkedto the desired configuration.

Many sportsmen who reload their spent straight wall cartridges employsimple, resizing dies which contains a single resizing ring. One suchdie is disclosed in U.S. Pat. No. 4,188,855 to Alberts. The Alberts dieis designed to be mounted in a resizing press so that the entire casingof a spent cartridge is passed through the single resizing ring of thedie. Accordingly, the entire casing of the cartridge is brought to asingle uniform diameter. The diameter is generally one which will enablea bullet to be securely press fitted into the open end of the casing.This diameter, however, can produce excessive compression of the chargechamber of the cartridge behind the bullet which adversely effects thefit and thus the performance of the reloaded cartridge when fired from aweapon. In addition, resizing a straight wall cartridge with a singlering oftentimes causes damage to the cartridge casing such that thecasing cannot be reloaded. The reason for this is because of thetolerances allowed suppliers of casings and bullets. Cartridge casingsuppliers are allowed a rather wide tolerance regarding casing diameterswhile suppliers of bullets are held to a close tolerance regardingbullet diameters. Manufacturers of single ring resizing dies must thusaccommodate the thinnest allowable casing wall thickness. The resizingring must be small enough to guarantee a sufficient press fit of abullet in the casing having the smallest allowable wall thickness. Thisnecessitates sizing rings that oftentimes are too small for the mainbody of the casing.

SUMMARY OF THE INVENTION

It is a primary object of the present invention to improve dies forresizing straight wall cartridges.

It is a further object of the present invention to improve theperformance of a spent straight wall cartridges that is reworked in aresizing die.

It is another object of the present invention to provide a relativelyinexpensive resizing die for spent straight walled cartridges that iscapable of reworking the casing of the spent cartridge to more than onediameter.

A still further object of the present invention is to prevent a straightwall shell cartridge from being damaged when being resized during areloading procedure.

These and other objects of the present invention are attained by a diefor resizing straight wall cartridges that includes an elongated bodythat can be mounted within a resizing press. The body contains anaxially extend bore that passes through the distal and proximal ends ofthe die body. A first resizing ring is located within the bore at thedistal end thereof through which the casing of a straight wall cartridgeis introduced into the die. A second resizing ring is mounted in axialalignment with the first resizing ring within the bore at a givendistance from the first resizing ring. The inside diameter of the firstresizing ring is larger than that of the second ring such that the sizeof the bullet accepting compartment of the cartridge casing is slightlysmaller than that of the charge storing compartment of the cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of these and other objects of the presentinvention reference will be made to the following detailed descriptionof the invention which is to be read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a side elevation showing a die embodying the teachings of theinvention mounted within a resizing press;

FIG. 2 is an enlarged perspective view of a side entry cartridge holderutilized in the resizing press shown in FIG. 1;

FIG. 3 is an enlarged side elevation of the die illustrated in FIG. 1with portions broken away to better illustrate sections of the die; and

FIG. 4 is an enlarged side elevation in partial section showing theconstruction of a typical straight wall cartridge.

DETAILED DESCRIPTION OF THE INVENTION

For ease of understanding, some components of the illustrated deviceswill be disclosed as having distal or proximal ends as well as havingtop, bottom or side surfaces. These terms are meant to be relative andnot necessarily limiting. By the same token, the term “straight wall”casing is used herein in the same manner as it is used in the art todistinguish the spent cartridge that is resized in the present die fromother cartridges known and used in the art such as bottleneck cartridgesand the like.

A typical straight wall cartridge ready for firing is illustrated inFIG. 4. The cartridge, generally references 10, contains a cylindricalshaped casing 11 that is opened at its distal end 12 and is providedwith a circular web 13 at its proximal end 14. The web is coaxiallyaligned with the central axis of the casing and contains a primer 17which is mounted in the primer pocket with flash hole 18 of thecartridge. The primer is arranged to be actuated by the firing pin of aweapon (not shown) to ignite a charge 15 that is stored in the chargecompartment A of the casing. A bullet 19 is press fitted into the bulletcompartment B of the casing which is expelled from the casing when thecharge is ignited. It has been found through testing that the bulletcompartment B and the charge compartment A of straight wall casingshould both be worked during the resizing operation to slightlydifferent diameters with the outer diameter of the charge section Abeing slightly larger than that of the bullet section B. This allows fora tight press fit of the bullet into the casing while at the same timeinsuring that the charge section is worked into a slightly larger smoothcircular configuration which insures that the casing will properly fitand expand into tight sealing contact against the firing chamber, of aweapon when the charge is ignited. Although the difference in the twocompartment diameters is relatively small, a marked improvement in theperformance of reloaded cartridges produced in this manner has beennoted.

Turning now to FIGS. 1 and 3, the resizing die, generally referenced 20,embodying the present invention is shown in greater detail. The dieincludes an elongated cylindrical body 21 that has a knurled head 23 atits upper proximal end 24. A bore enters the proximal end of the bodyand passes axially through the body and exits out of the distal end 27of the body. The outer surface of the body is provided with a malethread 30 that extends along a considerable length of the body. As bestillustrated in FIG. 1, the outer male thread 30 is adapted to mate witha female thread in either the stationary head 31 or the movable ram 32of a resizing press. In this case, the die is shown mounted in thestationary head 31 with the central axis 35 of the die being coaxiallyaligned with the path of travel 37 of the movable ram. The die issecured in a desired position within the stationary head by means of alock nut 38 that is mated to the outer threads of the die body andtightened against the upper surface 34 of the stationary head.

A spent cartridge 11 to be resized is shown mounted in an uprightposition upon the top surface 40 of movable ram 32 with the open distalend of the cartridge casing facing the prepositioned die. The cartridgeis shown secured in an upright posture by means of a side entryshell-holder 41 (FIG. 2) of the type commercially available from ReddingReloading Equipment of Cortland, N.Y. under the tradename E-Z Feed. Whenseated within the shell-holder, the casing 42 of the cartridge iscoaxially aligned with the bore of the die body. Actuating the closuremechanism of the press (not shown) will cause the open end of the shellcasing to be axially advanced into the bore of the die housing.

With further reference to FIG. 3, a pair of resizing rings are mountedwithin the bore of the die housing at the distal end 27 of the housing.These resizing rings include a first outer resizing ring 45 and a secondinner resizing ring 46. The rings are located within a radially expandedcylindrical retention chamber 48 that is machine to a desired depthwithin the distal end of the bore. The outside diameter of each resizingring forms a tight sliding fit with the inner wall of the retentionchamber that does not allow for radial movement of the ring within thechamber. In assembly, the inner ring is seated against the rear shoulder49 of the retention chamber and a cylindrical spacer 50 is placed inabutting contact against the outer face of the inner ring. The innerface of the outer resizing ring is mounted in abutting contact with thedistal end of the spacer. The depth of the retention chamber is suchthat the outer face of the outer ring is positioned just inside thedistal entrance to the die body bore when the ring is in abuttingcontact with the spacer. The ring assembly is secured in place againstaxial movement by mechanically crimping the rim 51 of the bore entranceagainst the outer face of the outer resizing ring.

The inside opening 53 of the outer resizing ring is such that the ringwill work a casing passing into the die to a first predetermineddiameter as the cartridge casing is advanced through the die. The insideopening 54 of the inner resizing ring is such that the inner ring willfurther resize that portion of the casing that is advanced therethroughto a second smaller diameter. The inside diameter of the spacer islarger than that of the outer ring so that the casing of the cartridgewill move freely through the spacer. Preferably, the resizing rings arefabricated of a carbide material, however, depending upon the casingmaterial, hardened steel or other similar materials may also be usedwithout departing from the teachings of the present invention.

The axial location of the two resizing rings within the die bore ispreset so that the outer resizing ring will shape the charge chamber ofa cartridge to a first predetermined diameter and the second innerresizing ring will shape the bullet chamber to a second slightly smallerdiameter when the spent cartridge casing is advanced to its full lengthinto the die body. In this particular case further advancement of thecasing is prevented by the shell holder 41 being intercepted by the rim51 at the entrance to the die bore. Any other type of stop capable oflimiting the axial penetration of the cartridge into the die might beused in the practice of the invention. It has been determined thatmaintaining the inside diameter of the outer resizing ring at between0.002″ and 0.010″ larger than that of the inside diameter of the innerresizing ring, the performance of a reloaded cartridge produced in thepresent die is considerably improved when compared to a reloadedcartridge that contains a casing that has been reworked to a singleuniform diameter.

The present die is equipped with a decapping unit 60 for removing aspent primer that is housed in the primer pocket of a cartridge as thecartridge casing advanced through the die bore. The decapping unitincludes a male threaded shank 65 that is arranged to mate with aninternal female threads located in the upper section of the die bore. Adecapping rod 66 is attached to the shank and extends downwardly intothe die bore. A decapping pin 67 protrudes from the lower end of the rodthat is capable of passing through the flash hole of the casing todislodge the spent primer from the primer pocket. As illustrated in FIG.3, both the decapping rod and pin are coaxially aligned with the axialcenterline 35 of the die bore. The upper end of the shank 65 is providedwith an enlarged head 70 to facilitate easy turning of the shank withinthe die bore to allow the unit to be adjusted within the die body.

While the invention has been described with reference to preferredembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof to adapt to particular situations without departingfrom the scope of the invention. Therefore, it is intended that theinvention not be limited to the particular embodiments disclosed as thebest mode contemplated for carrying out this invention, but that theinvention will include all embodiments falling within the scope andspirit of the appended claims.

1. A resizing die for producing two separate diameters in a straightwall casing of a spent cartridge that includes: a die body having adistal end and a proximal end, said die body further including a borethat passes into said die body through an opening in said distal end;said die body housing an outer resizing ring mounted in said opening atsaid distal end of said die body; said die body further housing an innerresizing ring mounted in said bore in axial alignment and at a givendistance from said outer resizing ring; and said outer resizing ringcontaining a first inside diameter that is larger than a second insidediameter that is contained in said inner resizing ring such that twoseparate diameters are produced within a casing of a spent straight wallcartridge that is advanced into said die body though said distal wallopening.
 2. The die of claim 1, wherein said first inside diameter ofsaid outer resizing ring is between 0.002″ and 0.010″ larger than saidsecond inside diameter of said inner resizing ring.
 3. The die of claim1, wherein each of said resizing rings is fabricated of a carbidematerial.
 4. The die of claim 1, that further includes spacer meanswithin said bore for maintaining said given distance between saidresizing rings.
 5. The die of claim 1, that further includes means foradjustably mounting said die body within a resizing press.
 6. The die ofclaim 1, that further includes a decapping means adjustably mountedwithin the bore of said die body for ejecting a primer from saidcartridge as said cartridge is advanced through said first and secondresizing dies.
 7. A die for resizing the casing of a spent straight wallcartridge that includes: an elongated die body having a distal end and aproximal end, said body further including a bore that passes axiallythrough said body between distal end wall and a proximal end wall; saidbore containing an axially aligned, radially expanded, cylindricalretention chamber having an open entrance at one end thereof that islocated in said distal end wall and a radially extended shoulder at itsother end; an inner resizing ring mounted within said retention chamberin abutting contact with said shoulder, said inner resizing ring havinga first inside diameter, a cylindrical spacer having a distal end and aproximal end mounted within said retention chamber with said proximalend of spacer in abutting contact with said inner resizing ring. anouter resizing ring mounted within said opening of said retentionchamber in abutting contact with said distal end of said spacer andhaving a second inside diameter that is larger than that of said innerresizing ring; and locking means for maintaining said outer resizingring within said opening in abutting contact with said spacer.
 8. Thedie of claim 7, wherein said locking means is a crimped rim thatsurrounds the entrance to said retention chamber which is in abuttingcontact with said outer resizing ring.
 9. The die of claim 7, whereinsaid inner and outer resizing rings are mounted in a tight slidingrelationship with an inside wall of said retention chamber to preventradial displacement of said resizing rings.
 10. The die of claim 9,wherein said cylindrical spacer has an inside diameter that is largerthan the inside diameter of said outer resizing ring.
 11. The die ofclaim 7, wherein said resizing rings are fabricated of a carbidematerial.
 12. The die of claim 7, wherein said die further includesmeans for adjustably mounting said die body within a resizing press. 13.The die of claim 7, that further includes a decapping means mountedwithin said bore for ejecting a primer from a cartridge that is advancedinto said bore through said distal end entrance.
 14. The die of claim 7,wherein the inside diameter of said outer resizing ring is between0.002″ and 0.010″ larger than that of said inner resizing ring.
 15. Thedie of claim 7, wherein said die body is cylindrical and contains a maleouter thread that extends along at least a portion of its outer surfacewhereby said die can be threaded into a die press.